Fluid treatment system and cleaning apparatus therefor

ABSTRACT

A cleaning apparatus ( 10 ) for a radiation source assembly ( 35 ) in a fluid treatment system is described. The cleaning apparatus comprise cleaning chamber ( 20 ) and a second chamber ( 25, 30 ) independent of the cleaning chamber which defines a fluid (typically water) buffer layer to obviate or mitigate cleaning fluid from the cleaning chamber leaking into the fluid being treated. The fluid treatment system is particularly useful for us in clean water applications in which ultraviolet radiation is used to treat the water while having the advantages of in situ cleaning of the radiation source when it becomes fouled.

This application claims the benefit of Provisional application Ser. No.60/136,766, filed May 28, 1999.

TECHNICAL FIELD

In one of its aspects, the present invention relates to a cleaningapparatus for use in a fluid treatment system. In another of itsaspects, the present invention relates to a fluid treatment systemcomprising the cleaning apparatus.

BACKGROUND ART

Fluid treatment systems are known generally in the art.

For example, U.S. Pat. Nos. 4,482,809, 4,872,980 and 5,006,244 (all inthe name of Maarschalkerweerd and all assigned to the assignee of thepresent invention and hereinafter referred to as the Maarschalkerweerd#1 Patents), the contents of each of which are hereby incorporated byreference, all describe gravity fed fluid treatment systems which employultraviolet (UV) radiation.

Such systems include an array of UV lamp frames which include several UVlamps each of which are mounted within sleeves which extend between andare supported by a pair of legs which are attached to a cross-piece. Theso-supported sleeves (containing the UV lamps) are immersed into a fluidto be treated which is then irradiated as required. The amount ofradiation to which the fluid is exposed is determined by the proximityof the fluid to the lamps, the output wattage of the lamps and thefluid's flow rate past the lamps. Typically, one or more UV sensors maybe employed to monitor the UV output of the lamps and the fluid level istypically controlled, to some extent, downstream of the treatment deviceby means of level gates or the like.

However, disadvantages exist with the above-described systems. Dependingupon the quality of the fluid which is being treated, the sleevessurrounding the UV lamps periodically become fouled with foreignmaterials, inhibiting their ability to transmit UV radiation to thefluid. For a given installation, the occurrence of such fouling may bedetermined from historical operating data or by measurements from the UVsensors. Once fouling has reached a certain point, the sleeves must becleaned to remove the fouling materials and optimize system performance.

If the UV lamp modules are employed in an open, channel-like system(e.g., such as the one described and illustrated in Maarschalkerweerd #1Patents), one or more of the modules may be removed while the systemcontinues to operate, and the removed frames may be immersed in a bathof suitable cleaning solution (e.g., a mild acid) which may beair-agitated to remove fouling materials. Of course, this necessitatesthe provision of surplus or redundant sources of UV radiation (usuallyby including extra UV lamp modules) to ensure adequate irradiation ofthe fluid being treated while one or more of the frames has been removedfor cleaning. This required surplus UV capacity adds to the capitalexpense of installing the treatment system. Further, a cleaning vesselfor receiving the UV lamp modules must also be provided and maintained.Depending on the number of modules which must be serviced for cleaningat one time and the frequency at which they require cleaning, this canalso significantly add to the expense of operating and maintaining thetreatment system. Furthermore, this cleaning regimen necessitatesrelatively high labor costs to attend to the requiredremoval/re-installation of modules and removal/re-filling of cleaningsolution in the cleaning vessel. Still further, such handling of themodules results in an increased risk of damage to or breakage of thelamps in the module.

If the frames are in a closed system (e.g., such as the treatmentchamber described in U.S. Pat. No. 5,504,335 (in the name ofMaarschalkerweerd and assigned to the assignee of the presentinvention), the contents of which are hereby incorporated by reference),removal of the frames from the fluid for cleaning is usuallyimpractical. In this case, the sleeves must be cleaned by suspendingtreatment of the fluid, shutting inlet and outlet valves to thetreatment enclosure and filling the entire treatment enclosure with thecleaning solution and air-agitating the fluid to remove the foulingmaterials. Cleaning such closed systems suffers from the disadvantagesthat the treatment system must be stopped while cleaning proceeds andthat a large quantity of cleaning solution must be employed to fill thetreatment enclosure. An additional problem exists in that handling largequantities of cleaning fluid is hazardous and disposing of largequantities of used cleaning fluid is difficult and/or expensive. Ofcourse open flow systems suffer from these two problems, albeit to alesser degree.

Indeed, it is the belief of the present inventors that, once installed,one of the largest maintenance costs associated with prior art fluidtreatment systems is often the cost of cleaning the sleeves about theradiation sources.

U.S. Pat. Nos. 5,418,370, 5,539,210 and 5,590,390 (all in the name ofMaarschalkereerd and all assigned to the assignee of the presentinvention and hereinafter referred to as the Maarschalkerweerd #2Patents), the contents of each of which are hereby incorporated byreference, all describe an improved cleaning system, particularlyadvantageous for use in gravity fed fluid treatment systems which employUV radiation. Generally, the cleaning system comprises a cleaning sleeveengaging a portion of the exterior of a radiation source assemblyincluding a radiation source (e.g., a UV lamp). The cleaning sleeve ismovable between: (i) a retracted position wherein a first portion ofradiation source assembly is exposed to a flow of fluid to be treated,and (ii) an extended position wherein the first portion of the radiationsource assembly is completely or partially covered by the cleaningsleeve. The cleaning sleeve includes a chamber in contact with the firstportion of the radiation source assembly. The chamber is supplied with acleaning solution suitable for removing undesired materials from thefirst portion of the radiation source assembly.

The cleaning system described in the Maarschalkerweerd #2 Patentsrepresents a significant advance in the art, especially when implementedin the radiation source module and fluid treatment system illustrated inthese patents. More specifically, the cleaning system described in theMaarschalkerweerd #2 Patents is particularly useful in municipalwastewater treatment facilities in which the cleaning system is employedin combination with an ultraviolet radiation treatment system disposedan open channel comprising a gravity fed flow of fluid. After treatment,the fluid is then discharged into a stream, creek, river, lake or otherbody of water.

Clean water treatment systems present a unique set of challenges sincethe fluid being treated in the system is a source of potable/drinkingwater. If the cleaning system described in the Maarschalkerweerd #2Patents were implemented in a clean water treatment system, there wouldbe a significant likelihood of leakage of the cleaning solution from thechamber into the fluid being treated. It is desirable to avoid suchleakage of cleaning solution from the cleaning system.

Thus, notwithstanding the advances in the art provided by the cleaningsystem taught in the Maarschalkerweerd #2 Patents, there remains a needin the art for a cleaning apparatus which may be implementedadvantageously, inter alia, in a clean water treatment system.

DISCLOSURE OF THE INVENTION

It is an object of the invention to provide a cleaning apparatus whichobviates or mitigates at least one of the above-mentioned disadvantagesof the prior art.

Accordingly, in one of its aspects, the present invention provides acleaning apparatus for use in a fluid treatment system comprising aradiation source assembly, the cleaning apparatus comprising:

-   -   at least one cleaning sleeve in sliding engagement with the        exterior of the radiation source assembly;    -   a first chamber disposed in the at least one cleaning sleeve in        contact with a portion of the exterior of the radiation source        assembly and for being supplied with a cleaning solution;    -   a second chamber disposed in the at least one cleaning sleeve        adjacent the first chamber;    -   seal means to restrict movement of fluid between the first        chamber and the second chamber; and    -   drive means to translate the at least one cleaning sleeve along        the exterior of the radiation source assembly.

In another of its aspects, the present invention provides a fluidtreatment device comprising a housing for receiving a flow of fluid, thehousing comprising:

-   -   a fluid inlet;    -   a fluid outlet;    -   a fluid treatment zone disposed between the fluid inlet and the        fluid outlet;    -   a radiation source assembly disposed in the fluid treatment zone        for treatment of the flow of fluid; and    -   a cleaning apparatus comprising: at least one cleaning sleeve in        sliding engagement with the exterior of the radiation source        assembly; a first chamber disposed in the at least one cleaning        sleeve in contact with a portion of the exterior of the        radiation source assembly and for being supplied with a cleaning        solution; a second chamber disposed in the at least one cleaning        sleeve adjacent the first chamber; seal means to prevent        substantially unrestricted movement of fluid between the first        chamber and the second chamber; first drain means to withdraw        fluid from the second chamber; and drive means to translate the        at least one cleaning sleeve along the exterior of the radiation        source assembly.

Thus, the present inventors have developed a novel cleaning device foruse in a fluid treatment system. The cleaning device contains two“independent” chambers. Specifically, there is provided a cleaningchamber for containing a cleaning solution in contact with an exteriorof a radiation source assembly. A second chamber is provided in thecleaning sleeve substantially adjacent the first chamber. The secondchamber, in essence, functions as a fluid (typically water) buffer layerbetween the cleaning chamber and the fluid being treated. Thus, thefluid buffer layer acts to receive small amounts of cleaning solutionwhich may leak from the cleaning chamber thereby obviating or mitigatingpassage of the cleaning fluid to the fluid being treated.

The cleaning chamber and the chamber defining the fluid buffer layer arerelatively “independent” of one another. This may be achieved by using aseal between the two chambers. Since even the highest quality seals arelikely to allow some leakage of cleaning fluid, the fluid buffer layerin the second chamber adjacent the cleaning chamber acts to obviate ormitigate alternate leakage of the cleaning fluid into the fluid beingtreated. This renders the present cleaning system advantageous for usein a clean water application where the fluid being treated is, forexample, potable water.

When implemented in a fluid treatment system for clean waterapplications, it is conventional to dispose the treatment system in aclosed pipe containing a pressurized (e.g., 150 psig) flow of water. Ifthe cleaning solution in the cleaning chamber and the fluid in thesecond chamber acting as the fluid buffer layer are maintained at apressure lower than the pressure of the fluid flow through the fluidtreatment system, there is, in essence, a pressure drop across theregion of the fluid flow and the two chambers of the cleaning device.This pressure drop assists in obviating or mitigating leakage of fluidfrom the cleaning chamber through the second chamber to the fluid beingtreated.

In a preferred embodiment, the second chamber defining the fluid bufferlayer further includes a drain to remove fluid from the second chamber.This further obviates or mitigates leakage of cleaning solution from thecleaning chamber through the second chamber to the fluid being treated.

In a father preferred embodiment, the cleaning chamber is provided witha supply and drain to add and remove cleaning solution to and from thecleaning chamber. In a further preferred embodiment, this supply anddrain in the cleaning chamber is comprised in a recirculation systemwhich allows for addition of cleaning solution, as required.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described with reference tothe accompanying drawings, in which:

FIG. 1 illustrates a schematic, in cross-section, of a preferredembodiment of the present cleaning device;

FIGS. 2 and 3 illustrate side elevations, in cross-section, of apreferred embodiment of a fluid treatment device comprising a preferredembodiment of the present cleaning apparatus;

FIGS. 4 and 5 illustrate enlarged side elevations, cross-section of thecleaning apparatus illustrated in FIGS. 2 and 3, respectively; and

FIGS. 6-8 illustrate photographs of a particularly preferred embodimentof the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to FIG. 1, there is illustrated a cleaning apparatus 10.Cleaning apparatus 10 comprises a cleaning sleeve 15. Cleaning sleeve 15comprises a cleaning chamber 20 and a pair of second chambers 25,30.Cleaning sleeve 15 is disposed over a radiation source assembly 35comprising a radiation source 40 enclosed within a protective sleeve 45.

Cleaning chamber 20 is separated from second chambers 25,30 by a pair ofseals 50,55.

Second chambers 25,30 are sealed from the exterior of the cleaningsleeve 15 by a pair of annular seals 60,65. Cleaning sleeve 15 isreversibly movable along the exterior of protective sleeve 45 in thedirection of arrow A. The actuation of cleaning sleeve 15 along theexterior of protective sleeve 45 will be described in more detailhereinbelow.

Cleaning sleeve 15 further comprises a drain 70 from each of secondchambers 25,30. Drain 70 may be utilized at atmospheric pressure.Ofcourse, the illustrated embodiment could be modified to have a singledrain from one of second chambers 25,30, and by providing communicationbetween second chambers 25,30. Further, a cleaning solution supply inlet75 is provided in cleaning sleeve 15 and serves to allow for supply ofcleaning solution to cleaning chamber 20. Also, a cleaning supply outlet80 is provided to allow for withdrawal of cleaning solution fromcleaning chamber 20.

With reference to FIGS. 2 and 3, there is illustrated a fluid treatmentdevice 100 comprising an inlet 105, an outlet 110 and a housing 115. Apair of opposed flanges 120,125 are disposed at opposite ends of housing115. A pair of opposed cover plates 130,135 are attached to flanges120,125, respectively, to provide, in the case of treating liquids, afluid-tight seal.

Disposed in housing 115 is a radiation source assembly 140 comprising apair of radiation, preferably ultraviolet radiation, lamps 145 disposedwithin a protective sleeve 150—e.g., a quartz sleeve.

Disposed adjacent cover plate 135 is a cleaning apparatus 200. Cleaningapparatus 200 comprises a pair of rods 205,210 which are slidablymoveable through cover plate 135. Attached to the ends of rods 205,210is a cleaning sleeve 300, the details of which will be described below.Attached to the other ends of rods 205,210 is a plate 215 which isconnected to a slide 219 movable along a rail 220. Rail 220 is aconventional electric screw drive which is connected to an electricmotor (not shown) or other electric motive means. The electric motorserves to rotate the screw (not shown) which translates slide 219 alongrail 220 thereby moving plate 215.

With reference to FIGS. 4 and 5, a more detailed explanation of thedesign of cleaning sleeve 300 will be provided. Thus, cleaning sleeve300 comprises a sleeve element 305 which surrounds and is movable overprotective sleeve 150 of radiation source assembly 140 (see FIGS. 2 and3). Sleeve element 305 includes a chamber 310 for receiving a cleaningfluid in FIG. 5, the cleaning fluid is shown in solid black. Cleaningchamber 310 is coupled to an elbow connector 315 which in turn iscoupled to rod 205 and, ultimately, plate 215. A line 320 is connectedto plate 215 and in turn to rod 205 via an elbow connector 325. Theother end of line 320 is connected to a supply of cleaning fluid (notshown). The cleaning fluid may be acetic acid or any other suitablefluid which will facilitate removal of fouling materials (e.g.,minerals, algae and the like) from the surface of protective sleeve 150.In essence, cleaning chamber 310 is defined by a pair of seals 330,335which, when sleeve 300 is mounted on quartz sleeve 150, form asubstantially fluid-tight type seal. Seals 330,335 are annular sealswhich surround quartz sleeve 150. Substantially adjacent seals 330,335are a pair of Teflon™ bearings 340,345, respectively.

Adjacent Teflon™ bearing 340,345 are a pair of second seals 350,355,respectively.

With reference to FIG. 4, in essence, Teflon™ bearings 340,345 aredisposed in a chamber 360 defined between seals 330,335 and 350,355,respectively. This can be seen clearly in FIG. 4 which illustrates aflow of fluid in black from second chamber 360.

Opposite elbow connection 315 attached to sleeve element 305 is anotherelbow element 365 which is connected to rod 210 and in turn to plate215.

As will be apparent, rod 210 includes a coaxial line which serves twopurposes. First, with reference to FIG. 5, cleaning fluid (shown inblack) may be removed from cleaning chamber 310 via an internal lin 370in rod 210. The disposition of line 370 in this manner creates a secondline 375 coaxially disposed around line 370. The function of line 375 isillustrated in FIG. 4 and served to remove fluid from second chamber360. Thus, rod 210 serves to both remove cleaning solution from chamber310 and independently remove fluid from second chamber 360.

Preferably lines 320 and 370 are connected to a recirculation pump whichallows for cleaning solution to be recirculate through clearing sleeve300 as illustrated in FIG. 5 (the cleaning solution is shown in black.Recirculation can be continuous or on a periodic basis. It should byapparent that the cleaning solution may be circulated in the reversedirection to that described above.

In operation, when it is desired to clean the exterior of protectivesleeve 150, the electrically driven screw (not shown) in rail 220 isactuated thereby moving plate 215 with respect to rail 220. This resultsin movement of cleaning sleeve 300 over protective sleeve 150. Suchcleaning can be done while fluid treatment device 100 is in operation orwhile it has been shut down for maintenance or another reason. Further,it is possible to design the dimensions of housing 115 such thatcleaning sleeve 300 may be parked in a position in housing 115 such thatit does not interfere with the hydraulic flow of fluid through thedevice. As will be apparent to those of skill in the art. FIG. 2 showsclearing sleeve in the filly extended (i.e, into housing 115) positionwhereas FIG. 3 illustrates cleaning sleeve in a retracted position

While the present invention has been described with reference topreferred and specifically illustrated embodiments, it will ofcourse beunderstood by those of skill in the arts that various modifications tothese preferred and illustrated embodiments may be made without theparting from the spirit and scope of the invention.

All publications, patents and patent applications referred to herein areincorporated by reference in their entirety to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

1. A cleaning apparatus for use in a fluid treatment system comprising aradiation source assembly, the cleaning apparatus comprising: at leastone cleaning sleeve in sliding engagement with the exterior of theradiation source assembly; a first chamber disposed in the at least onecleaning sleeve in contact with a portion of the exterior of theradiation source assembly and for being supplied with a cleaningsolution; a pair of annular second chambers on opposed sides of thefirst chamber and substantially surrounding the exterior of theradiation source assembly; seal means to restrict movement of fluidbetween the first chamber and each second chamber; and drive means totranslate the at least one cleaning sleeve along the exterior of theradiation source assembly.
 2. The cleaning apparatus defined in claim 1,further comprising first drain means to withdraw fluid from the secondchamber.
 3. The cleaning apparatus defined in claim 1, furthercomprising second drain means to withdraw cleaning fluid from the firstchamber.
 4. The cleaning apparatus defined in claim 1, furthercomprising supply means to supply cleaning fluid to the first chamber.5. The cleaning apparatus defined in claim 1, wherein the first chambercomprises a first annular chamber substantially surrounding the exteriorof the radiation source assembly.
 6. The cleaning apparatus defined inclaim 1, wherein the pair of annular second chambers are incommunication with one another.
 7. The cleaning apparatus defined inclaim 1, wherein the seal means defines a barrier between the firstchamber and the second chamber.
 8. The cleaning apparatus defined inclaims 1, further comprising second seal means disposed between the atleast one cleaning sleeve and the exterior of the radiation sourceassembly.
 9. The cleaning apparatus defined in claim 1, wherein theradiation source assembly comprises at least one radiation sourcedisposed in a protective sleeve.
 10. The cleaning apparatus defined inclaim 1, wherein the protective sleeve comprises a quartz sleeve.
 11. Afluid treatment device comprising a housing for receiving a flow offluid, the housing comprising: a fluid inlet; a fluid outlet; a fluidtreatment zone disposed between the fluid inlet and the fluid outlet; aradiation source assembly disposed in the fluid treatment zone fortreatment of the flow of fluid; and a cleaning apparatus comprising: atleast one cleaning sleeve in sliding engagement with the exterior of theradiation source assembly; a first chamber disposed in the at least onecleaning sleeve in contact with a portion of the exterior of theradiation source assembly and for being supplied with a cleaningsolution; a second chamber disposed in the at least one cleaning sleeveadjacent the first chamber; seal means to prevent substantiallyunrestricted movement of fluid between the first chamber and the secondchamber; first drain means to withdraw fluid from the second chamber;and drive means to translate the at least one cleaning sleeve along theexterior of the radiation source assembly.
 12. The fluid treatmentdevice defined in claim 11, wherein the cleaning apparatus furthercomprises first drain means to withdraw fluid from the second chamber.13. The fluid treatment device defined in claims 11, wherein thecleaning apparatus further comprises second drain means to withdrawcleaning fluid from the first chamber.
 14. The fluid treatment devicedefined in claim 11, wherein the cleaning apparatus further comprisessupply means to supply cleaning fluid to the first chamber.
 15. Thefluid treatment device defined in claim 11, wherein the first chambercomprises a first annular chamber substantially surrounding the exteriorof the radiation source assembly.
 16. The fluid treatment device definedin claim 11, wherein the second chamber comprises a pair of secondannular chambers on opposed sides of the first chamber and substantiallysurround the exterior of the radiation source assembly.
 17. The fluidtreatment device defined in claim 11, wherein the pair of second annularchambers are in communication with one another.
 18. The fluid treatmentdevice defined in claim 11, wherein the seal means defines a barrierbetween the first chamber and the second chamber.
 19. The fluidtreatment device defined in claim 11, wherein the cleaning apparatusfurther comprises second seal means disposed between the at least onecleaning sleeve and the exterior of the radiation source assembly. 20.The fluid treatment device defined in claim 11, wherein the protectivesleeve comprises a quartz sleeve.
 21. The fluid treatment device definedin claim 11, wherein the fluid treatment zone comprises a substantiallyelongate irradiation zone.
 22. The fluid treatment device defined inclaim 11, wherein the radiation source assembly comprises at least oneradiation source disposed in a protective sleeve.
 23. The fluidtreatment device defined in claim 11, wherein the at least one radiationsource is substantially elongate.
 24. The fluid treatment device definedin claim 11, wherein the at least one radiation source is disposedsubstantially parallel to a flow of fluid through the irradiation zone.25. The fluid treatment device defined in claim 11, wherein the at leastone radiation source is disposed substantially transverse to a flow offluid through the irradiation zone.
 26. The fluid treatment devicedefined in claim 11, wherein the fluid inlet, the fluid outlet and thefluid treatment zone are arranged in a substantially collinear manner.27. The fluid treatment device defined in claim 11, wherein the fluidinlet, the fluid outlet and the fluid treatment zone have substantiallythe same cross-section.
 28. The fluid treatment device defined in claim11, wherein the fluid inlet, the fluid outlet and the fluid treatmentzone are arranged in a substantially non-collinear manner.